Algebra


  1. If (x – 2) (x – p) = x2 – ax + 6, then the value of (a – p) is









  1. View Hint View Answer Discuss in Forum

    (x – 2) (x – p) = x2 – ax + 6
    ⇒  x (x – p) –2 (x – p)
    = x2 – ax + 6
    ⇒  x2 – px – 2x + 2p = x2 – ax + 6
    ⇒  x2 – x (p + 2) + 2p
    = x2 – ax + 6
    ∴  p + 2 = a
    (comparing respective co-efficients)
    ⇒  a – p = 2

    Correct Option: C

    (x – 2) (x – p) = x2 – ax + 6
    ⇒  x (x – p) –2 (x – p)
    = x2 – ax + 6
    ⇒  x2 – px – 2x + 2p = x2 – ax + 6
    ⇒  x2 – x (p + 2) + 2p
    = x2 – ax + 6
    ∴  p + 2 = a
    (comparing respective co-efficients)
    ⇒  a – p = 2


  1. If  
    1
    + x2 represents the redius of circle P and
    1
    + x = 17,
    x2x
    which of the following best approximates the circumference of circle P ?









  1. View Hint View Answer Discuss in Forum

    1
    + x = 17
    x

    On squaring both sides,
    x +
    1
    2 = 172
    x

    ⇒ 
    1
    + x2 + 2 = 289
    x2

    ⇒ 
    1
    + x2 = 289 − 2 = 287
    x2

    = radius of the circle
    ∴  Circumferece of circle = 2πr
    = 2 × 287 × π
    = 574π units

    Correct Option: C

    1
    + x = 17
    x

    On squaring both sides,
    x +
    1
    2 = 172
    x

    ⇒ 
    1
    + x2 + 2 = 289
    x2

    ⇒ 
    1
    + x2 = 289 − 2 = 287
    x2

    = radius of the circle
    ∴  Circumferece of circle = 2πr
    = 2 × 287 × π
    = 574π units



  1. If  
    a
    =
    1
    , find the value of the expression
    (2a − 5b)
    b2(5a + 3b)









  1. View Hint View Answer Discuss in Forum

    a
    =
    1
    b2


    = 2 ×
    1
    − 5
    2
    5 ×
    1
    + 3
    2

    =
    1 − 5
    =
    − 4 × 2
    5
    + 3 5 + 6
    2

    −8
    11

    Correct Option: C

    a
    =
    1
    b2


    = 2 ×
    1
    − 5
    2
    5 ×
    1
    + 3
    2

    =
    1 − 5
    =
    − 4 × 2
    5
    + 3 5 + 6
    2

    −8
    11


  1. If   a +
    1
    = 1 and b +
    1
    = 1 then c +
    1
    is equal to :
    bca









  1. View Hint View Answer Discuss in Forum

    a +
    1
    = 1
    b

    ⇒  a = 1 –
    1
    =
    b − 1
    bb

    ∴ 
    1
    =
    b
    ab − 1

    Again, b +
    1
    = 1
    c

    ⇒ 
    1
    = 1 – b
    c

    ⇒  c =
    1
    1 – b

    ∴  c +
    1
    =
    1
    +
    b
    a1 – bb − 1

    =
    1
    b
    =
    1 – b
    = 1
    1 – b1 – b1 – b

    Correct Option: A

    a +
    1
    = 1
    b

    ⇒  a = 1 –
    1
    =
    b − 1
    bb

    ∴ 
    1
    =
    b
    ab − 1

    Again, b +
    1
    = 1
    c

    ⇒ 
    1
    = 1 – b
    c

    ⇒  c =
    1
    1 – b

    ∴  c +
    1
    =
    1
    +
    b
    a1 – bb − 1

    =
    1
    b
    =
    1 – b
    = 1
    1 – b1 – b1 – b



  1. The value of  
    a
    +
    b
      is
    a − bb − a









  1. View Hint View Answer Discuss in Forum

    Expression =
    a
    +
    b
    a − bb − a

    =
    a
    b
    a − ba − b

    =
    a − b
    = 1
    a − b

    Correct Option: D

    Expression =
    a
    +
    b
    a − bb − a

    =
    a
    b
    a − ba − b

    =
    a − b
    = 1
    a − b